This application relates to a permanent magnet generator, wherein a control coil is provided such that a controlled, relatively constant output voltage can be achieved.
Generators are known, and are utilized to take in a source of rotation, and generate voltage output from that rotation. Typically, a source of rotation is attached to a rotor that has magnetic elements. The source of rotation drives the rotor relative to a stator having stator coils. The relative rotation induces a voltage in the stator coils.
One standard type of generator utilizes a permanent magnet rotor. Another type of generator utilizes field windings that are provided with an exciter field.
Each type of generator has certain deficiencies. A generator utilizing exciter coils may require a relatively large size, and a relatively large source of exciter field voltage.
Conversely, permanent magnet generators typically cannot supply a constant voltage over reasonable speed and load variation.
One typical source of the rotation to drive the rotor is a turbine rotor, such as in a gas turbine engine. Such a source of rotation cannot always provide a constant speed, and thus achieving a constant voltage with a permanent magnet generator driven by turbine rotors may prove challenging. The output voltage in a typical application is not constant over the variation in loads.